356
G. Kumar and H. Gupta
2 Review for Linear Fresnel Collector
For LFC technology, mean concentration ratios and maximum operating temperatures are reported between 10 and 30 and below 300 °C, respectively [14–18].
However, Abbas et al. [19] stated that by using high-quality mirrors, this technology
could reach as more as 500 °C with superheated water and 550 °C with molten
salt. According to the German Aerospace Center, this technology is still not reliable
and rated this as low maturity which can be said in a pre-commercial phase. This
announcement is an opportunity for the researcher to develop it to the next scale.
This happens because of the late improvement of the LFC in the particular CSP
advancement periods. Among line focus CSP technologies, LFC has less capital
cost because of light and simple structural support, geometrically flat reflectors, and
stationary absorber without moving joints. Considering shading and blocking effects,
patterns of alternating reflector inclination are established to make closely packed
reflectors. The requirement of the land area is less in this case because of its shape and
size. Although this technology has many advantages, maximum optical efficiency
found is 22% only due to cosine losses. But if the optical efficiency increases, then
this technology will give tough competition to PTC technology [14, 16]. Considering
the material of collector, LFC has the capability to improve the concentration ratio
and absorber temperature easily by putting some more reflectors without changing
system design requirements. Despite the ease of increasing the concentration ratio,
it is quite challenging to improve the optical efficiency of LFC. Receiver tubes are
typically limited to 450–550 °C with high-performance coating materials [9]. In
LFC, energy losses caused by the end effect also affect the length to width ratio of
the reflector. If the length to width ratio is beyond 1000, end effects are negligible.
In LFC, optical performance is significantly affected by energy losses due to cosine
[20].
2.1 LFC Development
This section describes the development of the LFC system from 1962. Several kinds
of prototype and industrial setup have been developed and tested for performance
analysis. The geometrical specifications of such an installed LFC prototype are shown
in Table 2. The LFC system can be installed either on rooftops or compact areas by
altering the length, width, or height of the receiver. It can be used to meet the process
heat or cooling demands of various sectors or industries [21].
Giovanni Francia LFC: In 1962, Giovanni Francia had patented his design for the
first real-world application as shown in Fig. 3. This design is tested for performance
investigation at Marseille, France. This setup has generated steam with an evaporating
capacity of 1965.38 kg/h at 450 °C and 100 atm [22].
G. Kumar and H. Gupta
2 Review for Linear Fresnel Collector
For LFC technology, mean concentration ratios and maximum operating temperatures are reported between 10 and 30 and below 300 °C, respectively [14–18].
However, Abbas et al. [19] stated that by using high-quality mirrors, this technology
could reach as more as 500 °C with superheated water and 550 °C with molten
salt. According to the German Aerospace Center, this technology is still not reliable
and rated this as low maturity which can be said in a pre-commercial phase. This
announcement is an opportunity for the researcher to develop it to the next scale.
This happens because of the late improvement of the LFC in the particular CSP
advancement periods. Among line focus CSP technologies, LFC has less capital
cost because of light and simple structural support, geometrically flat reflectors, and
stationary absorber without moving joints. Considering shading and blocking effects,
patterns of alternating reflector inclination are established to make closely packed
reflectors. The requirement of the land area is less in this case because of its shape and
size. Although this technology has many advantages, maximum optical efficiency
found is 22% only due to cosine losses. But if the optical efficiency increases, then
this technology will give tough competition to PTC technology [14, 16]. Considering
the material of collector, LFC has the capability to improve the concentration ratio
and absorber temperature easily by putting some more reflectors without changing
system design requirements. Despite the ease of increasing the concentration ratio,
it is quite challenging to improve the optical efficiency of LFC. Receiver tubes are
typically limited to 450–550 °C with high-performance coating materials [9]. In
LFC, energy losses caused by the end effect also affect the length to width ratio of
the reflector. If the length to width ratio is beyond 1000, end effects are negligible.
In LFC, optical performance is significantly affected by energy losses due to cosine
[20].
2.1 LFC Development
This section describes the development of the LFC system from 1962. Several kinds
of prototype and industrial setup have been developed and tested for performance
analysis. The geometrical specifications of such an installed LFC prototype are shown
in Table 2. The LFC system can be installed either on rooftops or compact areas by
altering the length, width, or height of the receiver. It can be used to meet the process
heat or cooling demands of various sectors or industries [21].
Giovanni Francia LFC: In 1962, Giovanni Francia had patented his design for the
first real-world application as shown in Fig. 3. This design is tested for performance
investigation at Marseille, France. This setup has generated steam with an evaporating
capacity of 1965.38 kg/h at 450 °C and 100 atm [22].